Well Bloomie23, you have asked one of these easy questions with hard answer. Not to mention unspecificness of question with so many possible answers.

First of all, I don't get it about what digital world You are talking. This world we live in is not a digital, it is analog. So it's pretty much understandable why analog systems "survive" even though digital systems seems superior to them.

From the above, it's quite clear that, in order to communicate with digital systems, we need conversion, and conversion is always source of irregularities, errors, noise, and everything else that might distort or degrade the original signal (and we don't want it).

When we talk about sound, CD-s compared to old vinyl disks sounds sterile (although CD-s don't suffer from cracks and noises like vinyl), and sound from vinyl sounds natural.

When we talk about synths, analog synths are part of the history of development of musical instruments, and therefore part of the music we listen (or listened). So if You want to have this specific sound, You will need original analog instrument, or at least good digital simulation. Of course simulation or copy cannot "beat" original by definition.

The reason why there are still more new analog synhts is the fact that analog electronic produce much thicker sound compared to digital synth, and it's preferable for use in creating music that resembles the time when analog sound was popular, or even modern "electronica" music.

Hope this helepad a bit.